Where can i buy a forgrip for an icon?

I want to buy an individual piece and want to know how much and where i can buy it.

if you don't know wut i mean by a foregrip its the part where the reg would go in...

the handle part you hold if u still don't get it...

THX,
Logan

and just making sure....i want to buy this part because my diablo's front block where the lpc block goes in broke and my pro shop replaced the front block with a icon's front block and the diablo's forgrip thingy didn't fit the icons front block threading soo now i have to buy a icons foregrip thing soo it fits....

just making sure the icon foregrip is the one when the frontblock screws into the forgrip right??